19,215 research outputs found

    ΔπN\Delta\pi N coupling constant in light cone QCD sum rules

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    We employ the light cone QCD sum rules to calculate ΔπN\Delta\pi N coupling constant by studying the two point correlation function between the vacuum and the pion state. Our result is consistent with the traditional QCD sum rules calculations and it is in agreement with the experimental value.Comment: 8 pages, latex, 2 figure

    Nucleons on the light-cone: Theory and phenomenology of baryon distribution amplitudes

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    This is a short review of the theory and phenomenology of baryon distribution amplitudes, including recent applications to the studies of nucleon form factors at intermediate momentum transfers using the light-cone sum rule approach.Comment: 16 pages, talk at CAQCD2006, Minneapoli

    Ultraviolet dominance of power corrections in QCD?

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    I explain current theoretical ideas on higher-twist (hadronization) corrections to physical observables in QCD.Comment: 7 pages, LATEX, no figures; Presented at 5th International Conference on Physics Beyond the Standard Model, Balholm, Norway, 29 Apr - 4May 199

    Deep Inelastic Scattering Beyond Perturbation Theory

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    I discuss possibilities to observe the instanton-induced contributions to deep inelastic scattering which correspond to nonperturbative exponential corrections to the coefficient functions in front of parton distributions of the leading twist.Comment: Talk given at the Leipzig workshop on High Energy Physics, Kyffhaeuser, September 20-24,1993, LATEX, 12 pages, 3 figures included as uu-encoded file, MPI-Ph/93-7

    Electroproduction of Resonances at Large Momentum Transfers

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    Measurements of transition form factors for the electro-excitation of nucleon resonances in the Q^2=5-14 GeV^2 region can provide one with the information on quark wave functions at small transverse separations. In particular a comparison of form factors for the states of opposite parity can give insight in the mechanisms of chiral symmetry breaking. I discuss perspectives of the theoretical description of such reactions using a combination of lattice calculations and light-cone sum rulesComment: 10 pages, 5 figures. Contribution to the Proceedings of the 4th Workshop on Exclusive Reactions at High Momentum Transfer, May 18-21, 2010 Thomas Jefferson National Accelerator Facility Newport News, Virginia US

    Renormalons and Power Corrections

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    Even for short-distance dominated observables the QCD perturbation expansion is never complete. The divergence of the expansion through infrared renormalons provides formal evidence of this fact. In this article we review how this apparent failure can be turned into a useful tool to investigate power corrections to hard processes in QCD.Comment: 56 pages, LaTeX, sprocl.sty. To be published in the Boris Ioffe Festschrift ``At the Frontier of Particle Physics/Handbook of QCD'', edited by M. Shifman (World Scientific, Singapore, 2001
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